Agricultural activities such as the use of fertiliser can result in the emission of nitrogen-containing compounds such as ammonia (NH₃) and nitrous oxide (N₂O) into the atmosphere. NH₃ is an air pollutant responsible for the formation of particulate matter, whilst N₂O is a powerful greenhouse gas. The greenhouse gases CO₂ and methane (CH₄) are also released during some agricultural activities, for example rice paddy farming releases large amounts of CH₄, and since methane and nitrous oxide are produced in greater quantities than CO₂ and have a higher global warming potential, they are considered the most significant greenhouse gases associated with farming.

Land use change is also a contributor to rising atmospheric greenhouse gas concentrations, mostly in the form of carbon dioxide. The IPCC special report on Land Use, Land-Use Change, and Forestry (2000) estimated that land-use change contributes a net 1.6 ± 0.8 Gt carbon per year to the atmosphere, primarily via the destruction of tropical forests and its conversion to agriculture.

Climate anomalies can also influence atmospheric composition. The El Niño Southern Oscillation (ENSO) is an irregular periodic variation in winds and sea surface temperature focused on the tropical eastern Pacific Ocean. Its warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña. ENSO is associated with many so-called ‘teleconnection’ effects, which are climate anomalies related to each other at large distances (typically thousands of kilometres).  Such teleconnections can result in large impacts on atmospheric composition even outside of the direct topical Pacific region. Tropospheric ozone, carbon monoxide, nitrogen oxide and smoke aerosols have all been found to increase in concentration over Maritime Southeast Asia in October during El Niño years, but also ENSO can lead to changes in precipitation and temperature in other regions that can alter atmospheric emissions there.

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